I have always been working in technical fields and one of the subjects I dealt with very often recently is Electric Motors.
I do translate lots of documents, technical sheets, specifications of EMs, but since I do not build them, it took a long time for me to understand how they work. And I am still studying and learning how they are manufactured, what type of motors are available on the market and I can assure you it’s quite a mess out there, as there are so many different options, powers, as well as different applications and purposes an electric motor can be used for.
Therefore I thought it might have been interesting for me (maybe for you too? I don’t know if you are also interested in technical stuff and you have no engineering degree as well as I haven’t) to get to know the (veeery) BASICS of an EM operating principle.
First of all, as an EM manufacturer I know said to me, “an electric motor is an energy transformer, its function is to change an energy type (electric power) into another one (mechanical power, motion)”.
Like an engine, using electric power instead of fuel combustion, though. But similarly to an engine, it is actually used as an actuator.
Engines move cars, EMs move many different things, such as conveyor belts, fans, lifts, etc.
An electric motor is composed of a stator and a rotor, which generate a magnetic field due to electric power running through the stator and magnets or poles mounted on the rotor. Between rotor and stator there is an air gap.
The magnetic fields causes the rotor to turn due to induction and, since the rotor is connected to a shaft, the shaft rotates too and is therefore able to transfer motion so something else (belt, fan…).
Electric motors can be synchronous, asynchronous, AC and DC.
Other specifications you might find are:
– step motors,
– brushless motors,
– linear motors,
– monophase motors,
– three-phase motor,
– brake motor,
– squirrel cage motors,
– slip ring motors,
– drum motors,
– double polarity motors, etc.
They can have special or extra features, such as:
– tropicalized windings,
– F Class and H Class insulation (motor maximum ambient temperature of respectively 40°C and 50°C)
– IP56 and IP65 protection, which
classifies and rates the degree of protection provided against the intrusion (including body parts such as hands and fingers), dust, accidental contact, and water by mechanical casings and electrical enclosures,
– extended shaft on non drive end side,
– reduced shaft end,
– reduced flange,
– low voltage,
– different terminal box positions,
– symmetrical winding,
– starting capacitor,
– special rating or voltage,
– commutator (for AC motors), etc.
Depending on the application, there are 9 different duty types:
S1 > continuous running duty
S2 > short time duty
S3 > intermittent periodic duty
S4 > intermittent periodic duty with starting
S5 > intermittent periodic duty with electric braking
S6 > continuous operation periodic duty
S7 > continuous operation periodic duty with electric braking
S8 > Continuous operation periodic duty with related load/speed changes
S9 > Duty with non-periodic load and speed variations
S10 > Duty with discrete constant loads
This is just a summary of all of the terms I encountered in my work, I do not have the technical knowledge to explain their operation in detail, but it was just an attempt to brainstorm a little bit and recap all of the variants I found!
Does anybody know any useful resources on EMs?